PR tree-optimization/59747

	* ree.c (find_and_remove_re): Properly handle case where a second
	eliminated extension requires widening a copy created for elimination
	of a prior extension.
	(combine_set_extension): Ensure that the number of hard regs needed
	for a destination register does not change when we widen it.

	PR tree-optimization/59747
	* gcc.c-torture/execute/pr59747.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@206638 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 59 insertions, 3 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1231e88b735..856bd46ac52 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2014-01-15  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/59747
+	* ree.c (find_and_remove_re): Properly handle case where a second
+	eliminated extension requires widening a copy created for elimination
+	of a prior extension.
+	(combine_set_extension): Ensure that the number of hard regs needed
+	for a destination register does not change when we widen it.
+
 2014-01-15  Sebastian Huber  <sebastian.huber@embedded-brains.de>
 
 	* config.gcc (*-*-rtems*): Add t-rtems to tmake_file.
diff --git a/gcc/ree.c b/gcc/ree.c
index 63cc8cc7c32..19d821ce05a 100644
--- a/gcc/ree.c
+++ b/gcc/ree.c
@@ -297,6 +297,12 @@ combine_set_extension (ext_cand *cand, rtx curr_insn, rtx *orig_set)
   else
     new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (*orig_set)));
 
+  /* We're going to be widening the result of DEF_INSN, ensure that doing so
+     doesn't change the number of hard registers needed for the result.  */
+  if (HARD_REGNO_NREGS (REGNO (new_reg), cand->mode)
+      != HARD_REGNO_NREGS (REGNO (orig_src), GET_MODE (SET_DEST (*orig_set))))
+	return false;
+
   /* Merge constants by directly moving the constant into the register under
      some conditions.  Recall that RTL constants are sign-extended.  */
   if (GET_CODE (orig_src) == CONST_INT
@@ -1017,11 +1023,20 @@ find_and_remove_re (void)
   for (unsigned int i = 0; i < reinsn_copy_list.length (); i += 2)
     {
       rtx curr_insn = reinsn_copy_list[i];
+      rtx def_insn = reinsn_copy_list[i + 1];
+
+      /* Use the mode of the destination of the defining insn
+	 for the mode of the copy.  This is necessary if the
+	 defining insn was used to eliminate a second extension
+	 that was wider than the first.  */
+      rtx sub_rtx = *get_sub_rtx (def_insn);
       rtx pat = PATTERN (curr_insn);
-      rtx new_reg = gen_rtx_REG (GET_MODE (SET_DEST (pat)),
+      rtx new_dst = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
 				 REGNO (XEXP (SET_SRC (pat), 0)));
-      rtx set = gen_rtx_SET (VOIDmode, new_reg, SET_DEST (pat));
-      emit_insn_after (set, reinsn_copy_list[i + 1]);
+      rtx new_src = gen_rtx_REG (GET_MODE (SET_DEST (sub_rtx)),
+				 REGNO (SET_DEST (pat)));
+      rtx set = gen_rtx_SET (VOIDmode, new_dst, new_src);
+      emit_insn_after (set, def_insn);
     }
 
   /* Delete all useless extensions here in one sweep.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4aadd851e85..dcfb67197f0 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-01-15  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/59747
+	* gcc.c-torture/execute/pr59747.c: New test.
+
 2014-01-15  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/59794
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr59747.c b/gcc/testsuite/gcc.c-torture/execute/pr59747.c
new file mode 100644
index 00000000000..d45a9082b81
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr59747.c
@@ -0,0 +1,27 @@
+extern void abort (void);
+extern void exit (int);
+
+int a[6], b, c = 1, d;
+short e;
+
+int __attribute__ ((noinline))
+fn1 (int p)
+{
+  b = a[p];
+}
+
+int
+main ()
+{
+  if (sizeof (long long) != 8)
+    exit (0);
+
+  a[0] = 1;
+  if (c)
+    e--;
+  d = e;
+  long long f = e;
+  if (fn1 ((f >> 56) & 1) != 0)
+    abort ();
+  exit (0);
+}